CN0335 Software User Guide

Overview

CN0335 provides robust and complete solution for ±10 voltage to digital conversion with isolation, for measurements where, voltage is used as standard interface. The design solution is optimized for high precision and low cost measurement, using only three active devices, and has a total unadjusted error of less than 0.1% FSR. The accuracy depends on the calibration.
The circuit shown in Figure 1 incorporates AD8606ARZ OpAmp, AD7091RBRMZ 12-bit successive approximation (SAR) ADC, and ADuM5401ARWZ isolator to create a standard ±10 voltage measurement system.
The circuit has 12 pin PMOD connector on board, which could be used for connection to a customer microprocessor or FPGA.
This CN0335 circuit note discusses the design steps needed to optimize the circuit shown in Figure 1 for a specific bandwidth including noise analysis and component selection considerations.

The performance of the circuit could be demonstrated with the use of Analog Devices SDP controller EVAL-SDP-CB1Z and SDP-to-PMOD Interposer Board SDP-PMD-IB1Z, both optional purchase items.
This user guide will discuss how to use the evaluation software to collect data from the EVAL-CN0335-PMDZ Evaluation Board CN0335

Installing the Software

Load the evaluation software by placing the CN0335 evaluation software disc in the CD drive of the PC. You can also download the most up to date copy of the evaluation software from www.analog.com/CN0335. Open the file setup.exe.

NOTE: It is recommended that you install the CN0335 Evaluation Software to the default directory path C:\Program Files\Analog Devices\CN0335\ and all National Instruments products to C:\Program Files\National Instruments\

Click Next to view the installation review page

Click Next to start the installation

Upon completion of the installation of the CN0335 Evaluation Software, the installer for the ADI SDP Drivers will execute.

NOTE: It is recommended that you close all other applications before clicking “Next”. This will make it possible to update relevant system files without having to reboot your computer.

\\

Press “Next” to set the installation location for the SDP Drivers.

It is recommended that you install the drivers to the default directory path C:\C:\Program Files\Analog Devices\SDP\DriversR2

Press “Next” to install the SDP Drivers and complete the installation of all software. Click “Finish” when done.

This indicator displays the current reading value. The value units depend on the chosen graph units (10).

Graph

This graph displays the collected data. The units on the graph depend on the chosen graph units (10).

Graph Controls

These controls allow the user to zoon in, zoom out, and pan through the data collected.

Graph Units Radio Buttons

This control determines the units of the data displayed in the chart and the numerical indicator.

System Status String Indicator

This indicator displays a message to the user detailing the current state of the software.

System Status LED Indicator

This indicator displays the current state of the software in the form of an LED. There are four status LED colors.InactiveBusyErrorWaiting for user action

Calibrate System Controls

These controls allow the user to calibrate the CN0335 Board. For the calibration two voltage inputs in the range ±10V are required. For best performance the inputs have to be selected “-10V” and “+10V”. To perform the calibration follow the instructions on the screen

SDP Firmware Revision

Read only data. After the connection is established with the SDP Board, the basic information for the controller can be found here.

Establishing a USB Connection Link

Follow the instructions to properly install the software and connect the hardware as described in the previous sections.

Open the file named CN0335.exe in the installation directory.

NOTE: If the software was installed to the default location it will be found at C:\Program Files\Analog Devices\CN0335\CN0335.exe

Click the Connect/Reconnect Button. A window with a progress bar will load.

Upon success, the System Status String Indicator will display SDP Board Ready to Acquire Data

Calibrating the CN0335 Board

Establish a USB Connection Link.

Click the Calibrate System tab.

Apply first calibration current to the input connector J2 of CN0335.

Write down the applied current to Calibration Current 1 indicator.

Press Calibrate 1 button.

Apply second calibration current to the input connector J2 of CN0335 and different from the previous calibration current.

Write down the applied current to Calibration Current 2 indicator.

Press Calibrate 2 button.

Capturing a Data

Establish a USB Connection Link.

Click the Run Button

Click the Stop Button when acquisition is complete.

Saving Data to a Spreadsheet File

Establish a USB Connection Link.

Capture Data.

Click the Save Data Button.

Click the OK Button.

Browse to the directory location where the spreadsheet file is to be saved.

Name the file.

Click the OK Button.

Open with Notepad or similar. The saved data shows the ADC Codes (decimal)

The software saves the spreadsheet file as ASCII text with columns separated by tabs.

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